Method and apparatus for transmitting and receiving convolutionally coded data for use with combined binary phase shift keying (BPSK) modulation and pulse position modulation (PPM)

Abstract

A method and apparatus for transmitting and receiving convolutionally coded data in a communication system employing a combination of Pulse Position Modulation (PPM) and Binary Phase Shift Keying (BPSK), wherein the code is selected to have error rate performance that is as good as the best convolutional code used with systems employing only BPSK.

1. A method for transmitting a sequence of data bits comprising the steps of:
 generating from said sequence of data bits a convolutional code comprising an output of at least first and second generators, the output of said first generator adapted to determine a transmit polarity of a respective one of said bits and the output of said second generator adapted to determine a transmit position of said respective bit, wherein an octal value of each of said generators has been chosen so as to maximize the dfree of said code while providing substantially the same performance of an optimum code which is adapted to determine only said transmit polarity; and 
 transmitting each bit of said sequence of data bits in accordance with said respective transmit polarity output of said first generator and said respective transmit position output of said second generator. 
 
   
   
     2. The method of  claim 1  wherein said convolutional code is systematic. 
   
   
     3. The method of  claim 1  wherein the octal value for said first generator is 2, and the octal value for said second generator is 5. 
   
   
     4. The method of  claim 1  wherein the octal value of each of said generators has also been chosen so as to minimize the number of parallel paths. 
   
   
     5. A method for transmitting a sequence of data bits comprising the steps of:
 generating from said sequence of data bits a convolutional code comprising an output of at least first and second generators, the output of said first generator adapted to determine a transmit polarity of a respective one of said bits and the output of said second generator adapted to determine a transmit position of said respective bit, wherein an octal value of each of said generators has been chosen so as to provide substantially the same performance as an optimum code which is adapted to determine only said transmit polarity; and 
 transmitting each bit of said sequence of data bits in accordance with said respective transmit polarity output of said first generator and said respective transmit position output of said second generator. 
 
   
   
     6. The method of  claim 5  wherein said convolutional code is systematic. 
   
   
     7. The method of  claim 5  wherein the octal value for said first generator is 2, and the octal value for said second generator is 5. 
   
   
     8. The method of  claim 5  wherein the octal value of each of said generators has also been chosen so as to minimize the number of parallel paths. 
   
   
     9. A method for transmitting a sequence of data bits comprising the steps of:
 generating from said sequence of data bits a BPSK+PPM convolutional code comprising an output of at least first and second generators, the output of said first generator adapted to determine a transmit polarity of a respective one of said bits and the output of said second generator adapted to determine a transmit position of said respective bit, wherein an octal value of each of said generators has been chosen so as to maximize the dfree of said code while providing substantially the same performance as an optimum BPSK-only code which is adapted to determine only said transmit polarity; and 
 transmitting each bit of said sequence of data bits in accordance with said respective transmit polarity output of said first generator and said respective transmit position output of said second generator. 
 
   
   
     10. The method of  claim 9  wherein said convolutional code is systematic. 
   
   
     11. The method of  claim 9  wherein the octal value for said first generator is 2, and the octal value for said second generator is 5. 
   
   
     12. The method of  claim 9  wherein the octal value of each of said generators has also been chosen so as to minimize the number of parallel paths. 
   
   
     13. A method for transmitting a sequence of data bits comprising the steps of:
 generating from said sequence of data bits a BPSK+PPM convolutional code comprising an output of at least first and second generators, the output of said first generator adapted to determine a transmit polarity of a respective one of said bits and the output of said second generator adapted to determine a transmit position of said respective bit, wherein an octal value of each of said generators has been chosen so as to provide substantially the same performance as an optimum BPSK-only code which is adapted to determine only said transmit polarity; and 
 transmitting each bit of said sequence of data bits in accordance with said respective transmit polarity output of said first generator and said respective transmit position output of said second generator. 
 
   
   
     14. The method of  claim 13  wherein said convolutional code is systematic. 
   
   
     15. The method of  claim 13  wherein the octal value for said first generator is 2, and the octal value for said second generator is 5. 
   
   
     16. The method of  claim 13  wherein the octal value of each of said generators has also been chosen so as to minimize the number of parallel paths.